The screen with touch function (touch screen) has been applied more and more widely. A capacitive touch screen is an important touch screen, the capacitive touch screen is provided with a plurality of driving electrodes (Tx) and a plurality of sensing electrodes (Rx) which intersect with each other, and a capacitance is generated at a position where the driving electrode and the sensing electrode are adjacent. The driving electrodes are loaded with driving signals in a scanning manner, and sensing signals are generated on the sensing electrodes accordingly. When touch happens, for example a human body or a touch pen closes to the touch region, the capacitance between the two kinds of electrodes in the touch region is influenced, and the sensing signal on the corresponding sensing electrode is changed, so that the touch position may be determined.
To avoid the electrodes from affecting the display, conventionally, the driving electrodes and the sensing electrodes are made of transparent conductive material such as indium tin oxide (ITO). However, the resistance of ITO is high, which may affect the touch effect. Therefore, Metal mesh technology has been proposed, that is, the driving electrodes and/or the sensing electrodes are made of metal material with low resistance, such as silver, aluminum, copper, molybdenum, niobium or alloy thereof, and since the metal is opaque, the electrodes are formed into mesh shape.
A kind of Metal mesh touch substrate is shown in FIG. 1 to FIG. 3, and may be a protection plate at the most outside of the display screen, a touch structure of it is provided at one side of a base 9 (this side faces towards the display panel), a circle of black matrixes are provided in the periphery of the base 9 and used to shield leads (not shown in drawings) of the touch structure, the leads are provided at one side of the black matrixes far away from the base 9 (when viewing from the base 9, the leads are shielded by the black matrixes) and used to connect the driving electrodes 1 and the sensing electrodes 2 to a touch chip. A plurality of driving electrodes 1 arranged in a row direction (a horizontal direction) and a plurality of sensing electrodes 2 arranged in a column direction (a vertical direction) are provided in the middle of the base 9. Each of the driving electrodes 1 consists of a plurality of driving metal meshes 11 of diamond shape in one row, two adjacent driving metal meshes 11 are directly connected through a connection portion 12, and each of the sensing electrodes 2 consists of a plurality of sensing metal meshes 21 of diamond shape in one column, the sensing metal meshes 21 and the driving metal meshes 11 are in the same layer, two adjacent sensing metal meshes 21 are connected through a connecting bridge 22, wherein the connecting bridge 22 may be made of indium tin oxide to be an ITO bridge. The driving metal meshes 11, the sensing metal meshes 21 and the connection portion 12 are all provided on the base 9 and formed simultaneously, and are covered by an insulation layer 4, the connecting bridge 22 is provided on the insulation layer 4 and is connected to the sensing metal mesh 21 through a via in the insulation layer 4, so that the driving electrode 1 and the sensing electrode 2 are prevented from being conducted at overlap position thereof. In FIG. 1, FIG. 4 and FIG. 6, the connecting bridge 22 is actually located on the insulation layer 4, and is in the different layer from the metal meshes and the connection portion 12. However, as the insulation layer 4 is transparent, the connecting bridge 22, the metal meshes and the connection portion 12 are visible when they are viewed from above.
In the above example, the driving metal meshes 11 and the sensing metal meshes 21 are diamond shaped, of course, they may be of other shapes, for example, strip shaped, so long as the driving electrodes 1 and the sensing electrodes 2, which intersect with each other, can be formed, and the adjacent metal meshes of the electrodes of different types may form a capacitance therebetween, which will not be discussed one by one herein.
It can be seen that, the touch structure of the Metal mesh touch substrate is provided on a substrate, belongs to an OGS (One glass solution) mode, which is beneficial to reduce the thickness of the touch screen. Meanwhile, since the electrodes are all formed in the same layer, only four procedures are needed: forming the black matrixes, forming a metal layer (including the driving metal meshes 11, the sensing metal meshes 21 and the connection portion 12), forming the insulation layer 4 with vias, and forming the connection bridge 22, therefore, the manufacturing method is simple.
However, the solution in which the driving metal meshes 11 and the sensing metal meshes 21 are provided in the same layer may bring about some problems, as shown in FIG. 1, a capacitance is mainly formed between the driving electrode 1 and the sensing electrode 2 by adjacent side surfaces of the driving electrode 1 and the sensing electrode 2 (in other words, edges of the metal meshes). However, the areas of the side surfaces of the metal meshes are very small, and when a driving electrode 1 and a sensing electrode 2 are adjacent, only a distance between protruding points of the mesh lines of the metal meshes, which are directly opposite to each other, indicates the small distance between the two electrodes, but distances between other portions of the electrodes are relatively large, resulting in a small capacitance between the driving electrode 1 and the sensing electrode 2, thus the signal-noise ratio is low, the detection effect is poor, and an existing touch chip cannot be applied thereto.